Key-seat rule



(No Moiiel.) l

' F. GRAM-BLITT;

KEY SEAT RULE. PatentedSept.2Z,1896gf.

Fig.1-

WITNESSES: lax/EN ER:

IWMLVJQLM Clad. a MM 7, ATTORNEY ATENT OFFICE.

FRANK ORAMBLITT, OF BALTIMORE, MARYLAND.

KEY-SEAT RULE.

SPECIFICATION forming part of Letters Patent No. 568,192, datedSeptember 22, 1896. Application filed June 3, 1896. Serial No. 594,082.(No model.)

1b all whom it may concern.-

Be it known that I, FRANK ORAMBLITT, a citizen of the United States,residing at Baltimore, in the State of Maryland, have invented certainnew and useful Improvements in Key-Seat Rules, of which the following isa specification.

This invention relates to a key-seat rule for use of machinists.

The object is to provide a simple and convenient tool for accuratelymarking a shaft where it is desired to cut a key-seat or other groove.

The invention is illustrated in the acco1npanying drawings, in which--Figure 1 is a side view of a shaft to which theimproved tool is applied.Fig. 2 is a crosssection of the shaft, showing the tool. Fig. 3 is aview of one end of one part and a section showing the cone-clamp. Figs.4 and 5 show the clamp part which holds one of the plates detachable.Figs. 6 and '7 show views of a modified form of tool.

Two parallel plates A A are hinged together, and each plate has astraight edge I) for ruling or marking accurately, and the two platesare provided with means for clamping and holding them at any desiredrelative position.

Referring to Figs. 1 to 5, one plate, A, has two half parts 0 of hinges,and each part c has a smooth-bore pivot-hole cl, which on one side istapered or countersunk. The other plate, A, has two corresponding halfparts 0 of the hinges. These are rigidly united by a rod 6. At each endthe half-hinge part c is tapped, as at f, for the pivot-screw andthreaded to receive said screw. Two screws G are used. The screw G ateach end has its threaded part passed freely through the pivot hole dinone of the hinge parts 0 and into the threaded hole of the part 0. Eachscrew has a cone-shaped shoulder h, which bears on the countersunk partof the pivot-hole cl and acts as a clamp to hold the hinge parts and thetwo plates immovable, so as to permit said plates to be set to suitlarger or smaller shafts and hold wherever set. The two screws G arereversely threaded, so that when turning them to tighten the hinges bothscrews will be turned in the same direction, and thus avoid the tendencyto a torsion twist which results when one is turned oppositely withrespect to the other. Provision is made for detaching one of the platesto admit of inserting a longer plate. This is done by making the twohalf-plates c of the hinge and the rod 0 one separate piece andproviding each of said half parts with a slot 1' and a set-screw j. Itwill thus be seen that a separate plate A may be inserted in said slott'.

Referring to the modification shown in Fig. 6 it will be seen that theparallel plates A A are hinged together, and in this case the half partsof the hinge are cast to each plate. Rigidly secured to the plate A is asegmentbar K, with a lug or stop Z, the purpose of which will bepresently pointed out. An arm K is rigidly secured to the plate A andhas a slottedhead L and a set-screw L. The segment-bar K passes throughthe slot in the head L and is held in any desired position by theset-screw. The stop-lug Z limits the spread of the plates. The operationis obvious.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent of the United States, is-- 1. In a key-seatrule the combination of two parallel plates, each having a straight edgeand half-hinge parts, those on one plate being tapped and screw-threadedand those 011 the other plate being bored and countersunk; and a screwuniting said half-hinge parts and having a cone-shaped shoulder whichbears on the countersunk bore, whereby the hinge parts and plates areclamped and held immovable.

2. In a key-seat rule the combination of two parallel plates each havinga straight, edge and hinged together at the edges opposite the saidstraight edges, and one of said plates being held by set-screws whichallow of its sep aration and detachment from the other plate; and meansfor holding said plates more or less open, as set forth.

In testimony whereof I EtffiX my signature in the prese r'ce of twowitnesses.

FRANK CRAMBLITT.

'Witnesses:

LEE I. VAN I-IoRN, CHARLES E. ll/IANN, Jr.

